Wrapped errors diff output is confusing

[dprotaso]

Two errors with the same messsage but constructed differently when compared produce a diff that looks identical

https://play.golang.org/p/i3y-6_rqonr

package main

import (
	"fmt"
	"errors"
	
	"github.com/google/go-cmp/cmp"
)

func main() {
	e1 := errors.New("Hello world!")
	e2 := fmt.Errorf("Hello %w", errors.New("world!"))
	
	
	fmt.Println(cmp.Diff(e1, e2))
}

Results in

 interface{}(
- 	e"Hello world!",
+ 	e"Hello world!",
  )

[dsnet]

Thanks for the report. It is a known issue with the reporter that it needs to do more work trying to disambiguate cases like these.

[dsnet]

Closing as duplicate of #194